1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor optical device.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2002-164622 discloses a technique concerning semiconductor optical devices. The semiconductor optical devices include a light-emitting device, a light-receiving device, and an optical modulator. The  semiconductor devices each have a mesa portion provided with an active layer having a light-emitting, light-receiving, or light modulating function. Further, the mesa portion is surrounded by a BCB (benzocyclobutene) resin. In addition, an electrode pad (bonding pad) made of a metal is provided on the BCB resin in order to make electric connection with the semiconductor optical device.
When an electrode pad is provided on the semiconductor optical device including a light-generating, -absorbing, or -guiding layer, a BCB resin region is interposed between the semiconductor optical device and the electrode pad in order to decrease a parasitic capacitance. When a bonding wire is mounted on the electrode pad, a tensile force is applied to the electrode pad. Therefore, the electrode pad and the BCB resin are desired to have bonding strength therebetween sufficient to resist the tensile force. However, the electrode pad is generally composed of a metal, and thus a combination of a metal and resin is difficult to provide enough bonding strength. In particular, a BCB surface contains a large amount of carbon component and is not easily strongly bonded to a metal. The insufficient bonding strength may cause separation of the electrode pad from the BCB resin when a bonding wire is mounted on the electrode pad.